Waterproof watchcase



Oct. 27, 1953 w. BONDY WATERPROOF WATCHCASE Filed April 19, 1949 IN VENTOR Patented Oct. 27, 1953 WATERPROOF WATCHCASE Wilhehn Bondy, Fribourg, Switzerland Application April 19, 1949, Serial No. 88,389 In Switzerland April 16, 1948 8 Claims.

This invention relates to timepieces, such as watches, clocks and the like.

In order to obtain water and dust tightness in Watches, clocks and the like, the several parts of the rigid watch or clock case have hitherto been fitted together with high precision. Sometimes, additional tightening means have been inserted in the joints. The reason for which penetration of dust and water vapour and, in consequence, the dirtying of the watch or clock movement and the oxydation of the lubricant has not been possible to be prevented in spite of the above-mentioned very expensive measures taken, resides in the fact that owing to the pressure differences between the interior of the case and the surrounding atmosphere, caused principally by fluctuations of the temperature, a certain exchange of air occurs in spite of the tightening means provided.

It is an object of the invention to prevent such an exchange of air and by this to do away with the reasons for which an adequate tightness of the timepieces is impossible in spite of precision and tightening means.

The invention relates to an air-tight timepiece, such as a watch, clock or the like and is characterised by a diaphragm separating the movement from the back of the case.

As materials for the diaphragm, principally all materials having a small directing force may be used, such as soft rubber, soft rubber-like artificial resins and metal foils especially of a, copper alloy, having a thickness of 3 to 200 microns, preferably microns, for instance.

A further object is to seal the case of the time- I piece on the side of the dial by cementing the joint between the crystal and the bezel by means of suitable materials such as sticking wax, pizein, sealing wax or shellac. When the crystal is made of Plexiglas, a solvent solving Plexiglas, such as acetone may be used. For the above sealing purposes, a ring of soft rubber might also be used, covering the joints in question or being inserted therein.

The accompanying drawing illustrates in an axial section one embodiment of the invention by way of example.

The movement 2 with the base plate I is held in the case 6 by the back 5 through the inter mediary of the spacing rings 3 and 4. The back 5 is screwed to the case 6. The crystal 1 is fixed to the case 6 in a well known manner, and the joint between the crystal and the caseband is covered by one (8) of the adhesive substances referred to above. A diaphragm 9 is clamped fast between the two spacing rings 3 and 4 along its circumference, and, owing to the small directing force of the material which it is made of, is able to move between the positions I and II owing to the differences in pressure between the spaces outside and inside of the diaphragm. Owing to the variation in the air volume in the space enclosed by the crystal, the case and the diaphragm, a compensation of the pressures in this space and in the surrounding atmosphere is obtained, in that the diaphragm moves towards the position I if the pressure in the case is higher than on the outside thereof, and towards the position II when the contrary is true. The compensation of pressure between the surrounding atmosphere and the air cushion between the diaphragm and the back takes place through the joints between the back on the one hand, and the case 6 and the spacing ring 4 0n the other hand, in that these joints are never air-tight. The bore for the winding stem may preferably be tightened by a gasor air-impermeable grease layer.

In this way any pressure difference between the space containing the movement and the surrounding atmosphere is avoided. Moisture and dust can no longer be sucked into the interior to the movement by a depression in the interior of the timepiece.

Due to the movement being enclosed by a diaphragm it becomes possible to fill the space enclosed by a gas, such as an atmosphere free from oxygen, excluding in this manner corrosion of the metal parts and of the lubricant in the timepiece. As an atmosphere free from oxygen, nitrogen and argon may be chosen for instance. The filling by gas may take place by methods wellknown in vacuum technics. The same result may be obtained by bringing substances l0 fixing oxygen and substances fixing water vapour into the space enclosed. As a substance fixing water vapour heated silica gel and as substances fixing oxygen sodium, potassium, rubidium, caesium may be used for instance.

On using organic crystals permeable to water vapour, the tightness may be improved by covering the inner face of the crystal by a layer impermeable to water vapour, such as an oil layer, for instance. On using crystals with several layers, it will be preferable to provide oil layers between the various crystal layers.

Should danger exist of a contact of the diaphragm with the movement having an injurious effect the movement may be protected from such 3 a contact by a grid, by sheet metal or by a wire piece.

It may be desired to cover the diaphragm which may also in this case consist of a soft rubberlike material or an artificial resin and which has a thickness of 5 microns for instance, by a layer having a very small power of solution for the plasticisers contained in the diaphragm. This layer may consist 'of a well-known substance'in which carbonisreplaced wholly or in part 'bysilicium, such as substances known under the trade name Silicon.

WhatIclaim is:

1. In a timepiece, a case portion, a crystal fixed to said case portion, a back fixed to' said case portion, and a deformable diaphragmof-athickness from 3 to 200 microns lying between said crystal and said back and being gas-tightly fixed to said case portion, said case portion, "crystal and deformable diaphragm enclosing together a 1 space variable in. size "by deformation :oisa'id diaphragm under the iniiuenceiof :a difference be"- tween the pressure in :said spacerand :th .pressureiin the surrounding.atmospherepand asm'ovement'enclosedin said space and spaced' 'from sai'd diaphragm.

v2. A timepiece comprising :a case iportion, ;a

crystal gas-tightly connected andsea IBdtQ-said case'pcrtion, a back "connected to saidtcasezpQrtion, a movement mounted within-saidcase portion in spaced relati'on to saidba'ck to :provide a space within the case portion 'between the-mov'e- 'ment and said back, a diaphragm :gas tightly connected to said case portion and ex-tending across said case portion withi'nzthe space 'pi'ovided between the movement andsaid hams-{said diaphragm beingof a thickness and formed-of material having a *small directive force which results in the materi'alhaving aneXtremely sma-ll resistance to deformation and being-readilytle flectable by variations in pressure between the atmosphere and the interior of said case portion closed by the crystal and said diaphragm so as to adjust the pressure within th case portion between the crystal and diaphragm to atmospheric pressure and still prevent the flow of atmospheric air into said portion.

3. A timepiece according to claim 2 in which "the diaphragm-consists of soft rubber.

"4. A timepiece according to claim 2 in which the diaphragm consists of a soft artificial resin.

5. A timepiece according to claim 2 in which thediaphrag-m consists of a Ni-Cu-alloy.

6. A timepiece according to claim 2 in which the space enclosed by the crystal, the case portionand thediaphragm is filled by gas. "'I.&A timepiece according to claim 2 in which the space enclosed by the crystal, the case portion-and the diaphragm contains means for removing water from the atmosphere therein.

8. -Aatimepiece-according to claim 2 in which the space enclosed by the'crystal, the case ;-por- =tionand xtheidiaphragm contains oxygen-reactive means.

WILHELM BONDY.

e Re fe'rences cited in the file of this patent "UNITED "STATES PATENTS Number Name Date 7 29,210 Woo'dworth July 17, 1860 969,680 Worrell 'Sept.'6, 1910 2341251; .Ditesheim Feb."8, 1944 "213821728 Kupchick Aug. 14, 1945 FOREIGN PATENTS Number Country Date Mar. 2085983 Switzerland June l,-l 940 215,706 Switzerland Oct. 16,1941 237 65? Switzerland e -Sept. 151-945 

